This invention relates generally to the valve art and more particularly to a valve for use with an aerosol container. Still more particularly, the invention relates to a novel valve assembly for use with an aerosol container for attaining a high degree of control in the dispensing of a substance disposed within the container under pressure.
Currently, many products are available in an aerosol dispensing package for consumer convenience. Such products permit dispensing from the container in which the product is stored and provides the additional advantage of convenient use or application of the product. For example, many paints are sold in an aerosol sprayable paint form which permits the user to apply the paint without the complication or mess of using a brush or other application device and the product is stored in the container from which it is dispensed.
The dispensing mechanism used with an aerosol product container is very important since this is an interface element of the product which helps determine whether or not the consumer will continue to use the product. If a dispensing mechanism is difficult to control or operate, or messy to operate, a consumer may discontinue use of such a product. Therefore, it is very important to provide a well engineered dispensing mechanism considering the human factors required to operate the mechanism. An additional factor to consider is how the dispensing mechanism operates in the controlled dispensing for an appropriate amount of product.
While many aerosol products merely require an on/off type valve, such that ether the valve is on and a continuous emission of product is released or the valve is off and no product is released, certain products, including aerosol foam require a high degree of precision or control in dispensing the product. For example, polyurethane foam sealants or other foam products are the type or products which require more precision in their application than merely an on/off type valve. Typically, these foam products are dispensed through the use of a tilt valve, however, the degree of control provided by the tilt valve is generally insufficient wherein precision control is necessary, unless the operator is highly skilled. The tilt valve does not provide sufficient magnification of the valve displacement to dispensing ratio and therefore provides a dispensing rate of product that is difficult to control. Nevertheless, the tilt valve has found use in the dispensing of aerosol foam products since more efficient alternatives have not been available, or were not economically feasible.
Further, polyurethane foam products swell substantially upon discharge from the container and therefore it is very important to provide precision control of the product to avoid waste, mess and damage resulting from too much product being dispensed and swelling within a confined area. The polyurethane foam product is a sticky material once dispensed which is capable of adhering to almost any surface and can be very difficult to remove especially since water actually accelerates the curing time of the product. Also, the muscle group used to control a tilt valve, either an index finger not in opposition with the thumb or a thumb not in opposition with an index finger, is not conducive of high precision control.
Generally, tilt valves and other aerosol valves are configured with a resilient gasket positioned between the valve and a top portion of the container to operatively seal the container yet permit unseating a portion of the valve when dispensing a product from the container. The ingredients in the liquid form of the polyurethane foam used in this application as well as the compatible propellants used with this product, in combination or alone, tend to have a deteriorating effect on the resilient gasket material. Deterioration of the gasket is manifested in hardening of the gasket which substantially reduces the shelf life of the product because once the gasket hardens (one to two months), the valve is no longer functional and the container may leak the polyurethane substance, propellant or both. While rigid materials have been found which are inert to commonly used propellants, resilient gasket material generally are not inert to such propellants, resilient materials which are inert to the propellants are deteriorated by the chemicals in the polyurethane substance.
Prior art valves have not provided solutions to the above-noted problems for the application of aerosol products in general and more specifically for the application of polyurethane foam products. Further, it was thought that the shelf life of polyurethane foam products could not be extended since many types and combinations of gasket materials have been tried in an attempt to overcome the deterioration problem caused by the chemicals in the liquid polyurethane material and the compatible propellant. However, the present invention has now solved the problems noted above in the dispensing of aerosol products.
The present invention, as will be detailed more fully hereinafter, overcomes the above-described problems. More specifically, the present invention provides a novel valve for use with an aerosol container for controllably dispensing a substance disposed within the container which is under pressure of a propellant also disposed within the container.